Bar codes are formed by printing a series of parallel bars. Numbers, letters or other characters and information are represented by a predetermined number of bars and spaces between bars. The number of bars, the width of the bars, and the spacing between the bars are arranged to convey the desired information. The quality of a bar code is directly affected by the accuracy with which the bar code is printed. A bar code printed with significant dimensional inaccuracies may not convey the desired information when it is scanned.